Tape handling apparatus



May 19, 1970 F. H. P. HORTON -TAPE HANDLING APPARATUS Filed May 10, 1968 CONTROL UN\T FAST REWIND SJGNAL INVENTOR FRED Cfltttk tam: Pgvmm 0mm! ATTORNEYS United States Patent O 3,512,692 TAPE HANDLING APPARATUS Frederick Henry Patrick Horton, Camberley, Surrey, England, assignor to International Computers and Tabulators Limited, London, England, a British company Filed May 10, 1968, Ser. No. 728,139 Claims priority, application Great Britain, May 16, 1967, 22,618/67 Int. Cl. B65h 59/36 US. Cl. 22625 6 Claims ABSTRACT OF THE DISCLOSURE A tape handler is described having a vacuum tape reservoir and a brake block to which suction is applied so as to apply a braking force to the tape. The suction supply for the brake block is derived from the vacuum tape reservoir so that during normal operation with a loop of tape in the reservoir, maximum suction is applied to the brake block whereas during a first rewind operation the tape is withdrawn from the reservoir thereby reducing the suction in the reservoir and hence the suction applied to the brake block.

BACKGROUND OF THE INVENTION This invention relates to tape handling apparatus.

US. Pat. No. 3,291,410 discloses a tape handling apparatus having a tape braking system which opeartes by applying suction to a surface of the tape from a stationary hollow brake block positioned adjacent the path of travel of the tape. The degree of suction applied, when braking is required, always has the same value irrespective of the particular phase of operation which is being performed by the apparatus. When braking is not required, the brake block is disconnected from the suction supply and is connected to a source of pressure by means of a valve.

SUMMARY OF THE INVENTION According to the invention web handling apparatus includes means operable to move a web longitudinally; an open ended reservoir; a suction source connected to the reservoir; means operable in a first phase of operation of the apparatus to feed the web along a first path in which the web is efiective as a barrier between the suction source and atmospheric pressure to produce a first pressure in the reservoir and operable in a second phase of operation of the apparatus to feed the web along a second path spaced from the open end of the reservoir to produce a second pressure in the reservoir; braking means responsive to air pressure in the reservoir and operable in response to said first pressure to apply a first braking force to the web and in response to said second pressure to apply a second braking force, less than said first braking force, to said web.

BRIEF DESCRIPTION OF THE DRAlVING The drawing shows a schematic view of part of a tape handling apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, tape handling apparatus includes a pair of capstans 1 and 2 rotating continuously in opposite directions. Pinch rollers S and 6 are positioned adjacent the capstans 1 and 2 respectively and one or other of the pinch rollers is moved electromagnetically to press a magnetic tape 3 against the corresponding capstem 1 or 2 to cause the tape to be moved either forwards or backwards past a transducer head assembly 4. In the drawing the pinch roller 5 is shown in its operated position pressing the tape against capstan 1 to drive the tape upwardly (in the drawing) past the head 4 whereas pinch roller 6 is shown in the unoperated position.

The ends of the tape 3 are wound on reels, of which one reel 7, together with its driving motor 8, is shown in the drawing. When one or other of the pinch rollers is operated a driving force is suddenly applied to the length of tape intermediate the reels. However the reels and driving motors have a relatively large inertia and hence stretching or braking of the tape 3 could occur. In order to prevent such an occurrence a loop 9 of tape is provided between each reel and the capstans. The loop 9 is drawn into and held in an open ended reservoir 10 by suction applied by a suction unit 14 to vents 11, 12 and 13 in the Walls of the reservoir 10. When drive is applied to the tape 3, the reel 7 cannot unwind, or wind up, the tape 3 instantaneously, but the tape at the capstans is able to move immediately without damage, the size of the loop 9 in the reservoir changing to allow for the different accelerations of the tape at the capstans and the tape a'djacent the reels. Similarly when the tape drive is suddenly removed, the tape at the capstans can stop almost instantaneously whereas the reels will decelerate relatively slowly, the difference in deceleration being accommodated by changing lengths of the tape loops.

The operation of the motor 8 is controlled by a control unit 30 which receives signals from tape loop position sensing devices 31, 32 and supplies power to the motor 8 to maintain the tape loop 9 at the desired position during steady movement of the tape and to restore the loop 9 to its desired position immediately after a change in the motion of the tape 3.

A guide roller 15 is provided to guide the tape 3 from the reel 7 into the reservoir 10. A pair of guides 28, 29 align the edge of the tape 3 correctly for passage past the head assembly 4. As mentioned above the other end of the tape 3, remote from the reel 7, is wound onto a second reel (not shown) and preferably a second loop is formed .in a second reservoir (not shown) between the capstan 2 and the second reel. A guide roller is provided between the second reservoir and the second reel.

The tape loop position sensing devices 31, 32 may be of the type described in co-pending British application Ser. No. 22,616/67 filed May 16, 1967, two sets of apertures 16 and 17 then being provided in the back wall of the reservoir 10 which are connected to ducts (not shown) to cause air flows which vary in dependence upon the tape loop positions relative to the sets of apertures 16 and 17. Thermistors (not shown) are positioned in the ducts so that the air flows act on the thermistors to produce signals indicative of the tape loop position.

Under fault conditions, it is possible for the loop 9 to become too long or too short, thereby taking up a position such as shown by chain-dotted lines 18 and 19 respectively. Two vents 20 and 21 are positioned adjacent the loog-loop and short-loop positions 18 and 19, respectively, but nearer the centre of the reservoir 10. Hence, when the loop 9 is in a normal position in the reservoir, such as that position indicated by a full line in the drawing, suction is applied to the vent 20 from the vent 13, and atmospheric pressure is applied to the vent 21 from the open end 22 of the reservoir 10. If the loop 9 reaches the position 18, the tape acts as a barrier between the vents 13 and 20 and the vent 20 now receives a higher pressure due to the atmosphere at the open end 22. On the other hand, if the loop 9 shortens to the position 19, the tape acts as a barrier between the open end 22 and the vent 21, so the vent 21 now receives suction from the vents 11, 12 and 13. 'In either fault condition, a loop fault detector 23 connected to the vents 20 and 21, responds to the change in pressure and causes the control unit 30 to shut down the apparatus- During a reading or recording operation of the apparatus, the reel motors are controlled so that tape loops occupy a central position in each of the two reservoirs. However, it is preferable during a fast rewind operation, to dispense with'o'ne loop, for example the loop 9 in the upper reservoir 10, thereby allowing a higher rewind speed. A fast rewind signal on line 33 causes the control unit 30 to disable the loop faultdetector 23 so that the loop 9 can leave the reservoir 10 without the apparatus shutting down. The tape 3 then takes up a posi-' tion, such as that represented by chain-dotted line 24, in which the tape 3 runs directly from the reel 7, past the pulley 15, over a guide roller 25 and past the capstans 1 and 2. Neither pinch roller 5 or 6 is operated by the control unit 30, the drive for the tape being supplied by the reel drive motors in accordance with a rewind routine such as described in our co-pending British application Ser. No. 22,617/67 filed May 16, 1967. During the rewind operation, a loop of the tape 3 still remains in the lower reservoir (not shown).

A braking force is applied to the tape 3 by a pair of hollow brake blocks 26 and 27 positioned adjacent the head assembly 4. Suction is applied to the interior of the blocks 26 and 27, and these blocks have apertures in a face adjacent the tape 3 so that the suction is applied to the tape 3 and resists movement of the tape. Although this braking force is intended to help the rapid deceleration of the tape 3 when driving force is removed from the tape, it is convenient to apply the suction to the blocks throughout operation of the tape handling apparatus.

However, the tape 3 is thereby subjected to a continuous drag which during a fast rewind operation causes an increase in tape tension. It is essential that tape tension should remain substantially constant whatever phase of operation is being performed by the apparatus, otherwise the tape 3 may be Wound irregularly onto the reels and damage to the tape may result.'Furthermore, at the high rewind speed the suction brakes may cause increased tape wear. It is advantageous, therefore, to reduce the suction during a rewind operation. However, it should not be completely removed. The brake blocks 26 and 27 therefore take their suction supply via the long tape loop detection vent 20 of the upper reservoir 10 (i.e. the reservoir from which the tape 3 is withdrawn during a fast rewind operation).

In operation of the apparatus, Whilst a loop 9 is contained in the upper reservoir 10, strong suction is applied from the suction unit 14, through the vent 13 (and possibly vents 11 and 12 depending on the loop position) to the vent and thence to the brake blocks 26 and 27. However, during a fast rewind operation the loop 9 is removed from the upper reservoir 10 and so the vent 20 receives suction from vents 11, 12 and 13 and atmospheric pressure from the open end 22. Hence a reduced suction is applied to the brake blocks 26 and 27 during the rewind phase of operation.

Clearly, modifications of this apparatus may be made without departing from the scope of the present invention. For example, the vent 20 associated with the loop fault detector 23 need not be used for the provision of suction for the blocks 26 and 27. A completely independent vent alongside the vent 20 could be used. Furthermore the reservoir 10 need not be a folded reservoir as "shown in the drawing but'coul'd' comprise' rn'erely'a' single compartment, provided that'the brake supply vent is correctly positioned in the compartment. The reservoir from which the brake suctionis taken could, alternatively, be an auxiliary reservoir formed inside or outside the main reservoir 10, provided that suction in thefauxiliary reservoir decreases during the rewind phase of operation. Means other than suction means could be provided for forming the loop 9 in the reservoir 10, suction then being applied to the reservoir 10 specially to provide the required supply for the brake blocks 26 and 27. Although it is preferable to retain a tape loop in one reservoir during a rewind operation, this is not essential.

Although the apparatus described above is for handling,

magnetic tape, clearly the invention is applicable to apparatus for handling any kind of web- I claim: 1 1. Web handling apparatus including means operable to move a Web longitudinally; anopen ended reservoir; a suction source connected to the reservoir; means operable in a. first phase of operation of the apparatus to feed the web along a first path in which. the web is effective as a barrier between the suction source and atmospheric pressure to produce a first pressure in the reservoir and operable in a second phase of operationof the apparatus to feed the web along a second path spaced from the open end of the reservoir to produce a second pressure in the reservoir; braking means responsive to air pressure in the reservoir and operable in response to said first pressure to apply a first braking force to the web and in response to said second pressure to apply a second braking force, less than said first braking force, to said web.

2. Web handling apparatus as claimed in claim 1 in which a loop of the web extends within the reservoir in the first phase of operation.

3. Web handling apparatus as claimed in claim 2 in which the reservoir is of elongate form having one end open and in which the suction source is connected to the reservoir at its other end.

4. Web handling apparatus as claimed in claim 3 in which the braking means is responsive to the pressure in the reservoir at its other end.

7 5. Web handling apparatus as claimed in claim 1 in which the braking means is operated by suction and is connected to the interior of the reservoir.

6. Web handling apparatus as claimed in claim 5 in which the braking means includes an element having a perforated face positioned adjacent the web and suction is applied through the perforated force to cause engagement of the web with said perforated face.

References Cited 

